The suspended small-particle layer in the oxygen-poor Black Sea: a proxy for delineating the effective N<sub>2</sub>-yielding section

Rasse, Rafael; Claustre, Hervé; Poteau, Antoine

doi:https://doi.org/10.5194/bg-17-6491-2020

Articles | Volume 17, issue 24

https://doi.org/10.5194/bg-17-6491-2020

© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/bg-17-6491-2020

© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 17, issue 24

Research article

|

23 Dec 2020

Research article |

| 23 Dec 2020

The suspended small-particle layer in the oxygen-poor Black Sea: a proxy for delineating the effective N₂-yielding section

Rafael Rasse, Hervé Claustre, and Antoine Poteau

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Final revised paper (published on 23 Dec 2020)
Preprint (discussion started on 08 Jun 2020)

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Status: closed

AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment

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RC1: 'Review of The suspended small-particles layer in the suboxic Black Sea: a proxy for delineating the effective N2-yielding section', Clara A Fuchsman, 07 Jul 2020
- AC1: 'Reply to the individual comments', Rafael Rasse, 15 Sep 2020
RC2: 'Review of "The suspended small-particles layer in the suboxic 1 Black Sea: a proxy 2 for delineating the effective N2-yielding section"', Anonymous Referee #2, 03 Aug 2020
- AC2: 'Reply to the individual comments', Rafael Rasse, 15 Sep 2020

Peer-review completion

AR: Author's response | RR: Referee report | ED: Editor decision

ED: Reconsider after major revisions (17 Sep 2020) by Aninda Mazumdar

AR by Rafael Rasse on behalf of the Authors (17 Sep 2020) Author's response Manuscript

ED: Referee Nomination & Report Request started (10 Oct 2020) by Aninda Mazumdar

RR by Clara A Fuchsman (28 Oct 2020)

Suggestions for revision or reasons for rejection

I thank the authors for expanding the introduction and discussion to include manganese oxides as a source of particles. I think this addition is important to the paper. However, the authors still need to add in references to previous work on the organic matter maximum at the redox interface In the Black Sea. Just one or two sentences acknowledging this previous work seems important since this organic matter maximum is the focus of the present paper.
Important papers about the organic matter maximum in the Black Sea redoxycline: (Coban-Yildiz et al., 2006; Yilmaz et al., 2006; Glaubitz et al., 2010; Ediger et al., 2019)
Perhaps add these new sentences around line 29 of the introduction.

Detailed comments
Poorly oxygenated isn’t a scientific term. I think the term you are looking for is suboxic.
Line 28: the fact that some SAR11 can reduce nitrate is from (Tsementzi et al., 2016). I know you cite this paper later, but it would be good to cite it here too.
Line 31: N2 yielding bacteria—the noun is necessary
Line 77: N2 yielding bacteria
Line 174: The epsilonproteobacteria Sulfurimonas is one of the most important sulfur oxidizers in the Black Sea. See (Glaubitz et al., 2010) also (Kirkpatrick et al., 2018) figure 7. This epsilon proteobacteria is likely an autotrophic denitrifier (Fuchsman et al., 2012). Might be a better sulfur oxidizer to single out than SUP05—or name them both.
Line 312: Actually, your results do not suggest that the particle layer is due to the list of bacteria. Previous work suggests this. For example (Glaubitz et al., 2010) or (Kirkpatrick et al., 2018). You assume that this is the case. Please rephrase.

References
Coban-Yildiz, Y., Altabet, M.A., Yilmaz, A., and Tugrul, S. (2006) Carbon and nitrogen isotopic ratios of suspended particulate organic matter (SPOM) in the Black Sea water column. Deep Sea Res Part II Top Stud Oceanogr 53: 1875–1892.
Ediger, D., Murray, J.W., and Yılmaz, A. (2019) Phytoplankton biomass , primary production and chemoautotrophic production of the Western Black Sea in April 2003. J Mar Syst 198: 103183.
Fuchsman, C.A., Murray, J.W., and Staley, J.T. (2012) Stimulation of autotrophic denitrification by intrusions of the Bosporus Plume into the anoxic Black Sea. Front Microbiol 3:.
Glaubitz, S., Labrenz, M., Jost, G., and Jürgens, K. (2010) Diversity of active chemolithoautotrophic prokaryotes in the sulfidic zone of a Black Sea pelagic redoxcline as determined by rRNA-based stable isotope probing. FEMS Microbiol Ecol 74: 32–41.
Kirkpatrick, J.B., Fuchsman, C.A., Yakushev, E. V., Egorov, A. V., Staley, J.T., and Murray, J.W. (2018) Dark N2 fixation: nifH expression in the redoxcline of the Black Sea. Aquat Microb Ecol 82: 43–58.
Tsementzi, D., Wu, J., Deutsch, S., Nath, S., Rodriguez-R, L.M., Burns, A.S., et al. (2016) SAR11 bacteria linked to ocean anoxia and nitrogen loss. Nature 536: 179–183.
Yilmaz, A., Coban-Yildiz, Y., Tellikarakoc, F., and Bologa, A. (2006) Surface and mid-water sources of organic carbon by photoautotrophic and chemoautotrophic production in the Black Sea. Deep Sea Res Part II Top Stud Oceanogr 53: 1988–2004.

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ED: Publish subject to minor revisions (review by editor) (30 Oct 2020) by Aninda Mazumdar

AR by Rafael Rasse on behalf of the Authors (06 Nov 2020) Author's response Manuscript

ED: Publish as is (11 Nov 2020) by Aninda Mazumdar

AR by Rafael Rasse on behalf of the Authors (12 Nov 2020) Author's response Manuscript

Short summary

Here, data collected by BGC-Argo floats are used to investigate the origin of the suspended small-particle layer inferred from optical sensors in the oxygen-poor Black Sea. Our results suggest that this layer is at least partially composed of the microbial communities that produce dinitrogen. We propose that oxygen and the optically derived small-particle layer can be used in combination to refine delineation of the effective N₂-yielding section of the Black Sea and oxygen-deficient zones.

The suspended small-particle layer in the oxygen-poor Black Sea: a proxy for delineating the effective N2-yielding section

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The suspended small-particle layer in the oxygen-poor Black Sea: a proxy for delineating the effective N₂-yielding section